High-throughput screening instruments (or analyzers) are critical tools in the pharmaceutical research industry and in the process of discovering and developing new drugs. High-throughput analyzers are used to assess the efficacy of candidate drug compounds. Dramatic increases in the number of these compounds and in the number of targets against which they may be directed have created a bottleneck in the development of new drugs and a need for analyzers that can operate with a high degree of analytical flexibility and speed. Analytical flexibility and speed are necessary because high-throughput applications may involve repeating the same operations hundreds of thousands of times, greatly magnifying even the smallest shortcomings.
One way to increase speed and analytical flexibility is to house a variety of small-volume samples in a single container. Toward this end, high-density containers known as microplates have been developed. Microplates are generally rectangular containers that include a plurality of sample wells for holding a plurality of samples. Microplates enhance speed by reducing transit time between samples and reduce cost by employing small amounts of reagents. Unfortunately, microplates also have a number of shortcomings. For example, microplates do not conform to any exact standard, so that their size, shape, and construction materials may vary, depending on vendor or batch. In addition, microplates may vary from opaque to transparent, so that analytical approaches developed for some microplates will not work for other microplates. Moreover, preferred microplates may differ, depending on application. Furthermore, microplates may allot only a small volume for each sample, reducing signal and making it easier to spill sample during transit.
Another way to increase speed and analytical flexibility is to use robots and other devices to automate high-throughput screening procedures. For example, robots permit analyzers to run 24 hours a day. Unfortunately, current robotic systems have a number of shortcomings. For example, robots may have difficulty setting and positioning a sample container in a holder, particularly if different sample containers are of different sizes.
Another way to increase speed and analytical flexibility is to use a luminescence assay. These assays typically are run in the dark, so that analyzers must be placed in a housing or in a light-tight room, which is darkened when the analyzer is in use. Unfortunately, such an approach has a number of shortcomings. For example, the housing may block convenient access to the examination area, where samples are analyzed. The light-tight room may require a dedicated room, which wastes space. The light-tight room also may require the operator of the optical system to work in the dark, which is inherently unsafe, because the operator may have difficulty seeing the equipment, and because the operator may become drowsy.